disabled thread sanitizer for a few clang versions - see these builds: https://travis-ci.org/onqtam/doctest/builds/417926743
diff --git a/.travis.yml b/.travis.yml
index 5edc5dc..24dea31 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -117,14 +117,14 @@
           sources: *apt_sources
 
     # Clang 3.5
-    - env: COMPILER=clang++-3.5 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true
+    - env: COMPILER=clang++-3.5 HAS_ASAN=true HAS_UBSAN=true # no HAS_TSAN - see errors: https://travis-ci.org/onqtam/doctest/builds/417926743
       addons: &clang35
         apt:
           packages: ["clang-3.5", "valgrind", "libc6-dbg", "g++-6"]
           sources: *apt_sources
 
     # Clang 3.6
-    - env: COMPILER=clang++-3.6 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true
+    - env: COMPILER=clang++-3.6 HAS_ASAN=true HAS_UBSAN=true # no HAS_TSAN - see errors: https://travis-ci.org/onqtam/doctest/builds/417926743
       addons: &clang36
         apt:
           packages: ["clang-3.6", "valgrind", "libc6-dbg", "g++-6"]
@@ -138,7 +138,7 @@
           sources: *apt_sources
 
     # Clang 3.8
-    - env: COMPILER=clang++-3.8 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true
+    - env: COMPILER=clang++-3.8 HAS_ASAN=true HAS_UBSAN=true # no HAS_TSAN - see errors: https://travis-ci.org/onqtam/doctest/builds/417926743
       addons: &clang38
         apt:
           packages: ["clang-3.8", "valgrind", "libc6-dbg", "g++-6"]